This invention relates to the handling of web material between spaced web handling means such as between a dryer, or the like, and a calender, or the like, and is more particularly directed to new and improved apparatus for and method of suppressing flutter during high speed operation with thin, light weight paper web such as tissue paper.
Serious limitations have heretofore been encountered in the speed at which web material such as tissue paper, plain or creped could be handled. Because of its light weight and frangible nature tissue paper web has been prone to break in unsupported generally horizontal open draws such as between the dryer and calender.
Direct support of the traveling web on a stationary member produces a drag force and strain on the web, which reduces the crepe where creped tissue is being handled. On the other hand, rotary transport members tend to function as air transport pumps by inducing a corotating band of air which is interposed between the rotating member and the web, and this contributes to web instability as it travels over the rotating members. An additional problem with supporting traveling webs on rotating members is that the so called "table roll effect" (i.e. the tendency of the traveling web to follow the surface of the rotating roll and thus wrap the roll, at which point the web is, of course, broken) produces strain in the web which can cause the web to flap and break. Frequently the broken web then wraps the rotating roll and must be cut off and rethreaded before operation can be resumed.
If the web is left unsupported, stray air currents and even tension wrinkles in the web will cause the web to become unstable and the resulting flutter and strains in the web eventually cause it to break.